Events

Responses of a montane fauna to 100 years of climate change

In the early 20th Century, Joseph Grinnell and colleagues in the Museum of Vertebrate Zoology at UC Berkeley had the foresight to establish a rich and specimen-backed database of distributions of small mammals and birds throughout California, including transects spanning the steep environmental gradients of the Sierra Nevada. Some 80-100 years later, the MVZ has completed resurveys of these transects to document range dynamics in response to environmental change. After applyingrigorous occupancy-based models to control for differences in detectability, we observed a preponderance of upwards shifts of small mammals, consistent with response to increased minimum temperatures. For some formally high elevation species, this has resulted in severe range contractions. By comparison, birds are as likely to have moved down as up; this heterogeneity appears to reflect response to local change in either temperature or precipitation or to both. The challenge now is to understand heterogeneity of species' responses. To that end current studies are integrating genomic, isotopic, physiological and ecological approaches, including novel uses of museum specimens.